This invention is in the field of solid-state imaging detectors for infrared. Various types of such detectors have been proposed, but have been difficult to make with good definition, low noise figures, and high quantum efficiencies. The instant invention takes advantage of the known (and desirable) silicon-insulator-polysilicion (SIP) on-chip growth technology. Extrinsic detectors using such a technology may be produced, but such detectors have low optical density in the infrared and require thicknesses incompatable with SIP. The instant invention is able to use SIP, and by using orientionally dependent etching (ODE), the thickness requirement for detectors is transformed into a lateral dimension. Exemplary reference for the above-mentioned technology are the book Basic Integrated Circuit Engineering by Hamilton and Howard, published in 1975 by McGraw-Hill Book Co. and bearing Library of Congress Catalog Card No. 74-23921, and the periodical Proceedings of the IEEE of January 1975. Pages 83-88 of the book and pages 63-66 of the periodical are particularly pertinent. Moreover, a "classical" paper on oriential etching is the paper by Bean and Gleim on pages 1469-1476 of Proceedings of the IEEE, Vol. 57, No. 9, of September 1969. A more recent article on ODE is on pages 545-552 of the April 1975 edition of the Journal of the Electrochemical Society.